The tough, sword-shaped leaves grow up to three metres long and up to 125 mm wide. They are usually darkish green but sometimes have coloured edges and central ribs. Cultivated varieties range from light green through pink to deep russet bronze. There are numerous variegated cultivars with leaves marked by contrasting stripes in shades of green, red, bronze, pink and yellow.
The rigid flower stalks can be up to five metres long, projecting high above the foliage. In November (in New Zealand) they produce clumps of curving tube-like flowers which turn bright red when mature. These produce unusually large quantities of nectar to attract all nectar feeding birds such as the tui and insects. The seedpods that develop after pollination, each contain hundreds of seeds which are later widely dispersed by the wind.